Device for making a wire strand with changing twist direction

ABSTRACT

A device for making a wire strand with changing twist direction (SZ-stranding) from individual wires, includes a fixed guide (1) provided with bores for receiving the individual wires and a plurality of spaced apart storing disks (4) capable of being driven in changing directions and also having bores for receiving the individual wires to be stranded, and a laying disk (6) capable of being driven via drive disks (7) and transmission members (9), with a drive (8) common to at least a portion of the drive disks (7) being provided, wherein between the drive (8) and the drive disks (7) there is disposed a torsionally elastic shaft (15) having an arbitrary cross-section.

BACKGROUND OF THE INVENTION

The invention relates to a device for making a wire strand with changingtwist direction (SZ-stranding) from individual wires and in particularto a device of a type a fixed guide provided with bores for receivingthe individual wires and a plurality of spaced apart storing diskscapable of being driven in changing directions and also having bores forreceiving the individual wires to be stranded, and a laying disk capableof being driven via drive disks and transmission members.

In known devices of this type, the laying disks are driven by theassociated driving disks via mechanisms with correspondingly differentspeed increasing ratios. This, however, has the disadvantage thatrelatively large masses have to be braked within a short time andaccelerated again in the opposite direction. This is especiallydisadvantageous for those laying disks which have a large twistingangle.

SUMMARY OF THE INVENTION

It is the object of the invention to obviate these disadvantages and topropose a device of the abovementioned type where the direction of onlyrelatively small masses will have to be reversed.

The object of the invention is achieved by providing a drive common toat least a portion of the drive disks, wherein between the drive and thedrive disks there is disposed a torsionally elastic shaft having anarbitrary cross-section. These features make it possible that at least aportion of the drive disks connected to each other via the torsionallyelastic shaft does not require a separate speed increasing mechanism,since this function is provided by the torsionally elastic shaft. Thedecreasing twisting angles required for proper stranding which decreasein relation to the fixed guide, result from the decreasing twist of thetorsionally elastic shaft in relation to its fixed end.

A preferred embodiment of the invention for wire stranding machineswhere large stranding forces for the items to be stranded are required,includes at least two adjacent drive disks coupled together via a rigidshaft, with the drive disks having different speed increasing ratioswith respect to their associated laying disks.

The twisting action is at all possible and can be improved bymaintaining the torsionally elastic shaft under tension.

Preferably, the torsionally elastic shaft is formed as a torsion springor a torsion bar which is connected to the drive disks in a torsion-freemanner. This is from an engineering standpoint, a very simple solution.

According to another feature of the present invention, the springconstant of the torsion spring and the torsion bar, respectively,increases in the direction towards the drive. In this manner, adifferent stiffness of the spring or rod, as the case may be, isobtained along the length of the torsion spring or the torsion bar,respectively, whereby the mass inertia of the torsionally elastic shaftcan be compensated at high accelerations.

In one embodiment of a device of the invention the excursion of thefilament-shaped or strip-shaped element and the lengthening causedthereby, creates a corresponding restoring force, resulting in an actionsimilar to a torsion spring, wherein, however, the filament-shaped orstrip-shaped element itself does not experience a significant torsion.If the radial distance between the bores for receiving thefilament-shaped or strip-shaped element and the rotation axis of thedrive disks is increased when moving in the direction from the fixedguide towards the motor, then the twisting angles of the laying diskswill in turn decrease when moving from the region proximate to the motorto the region proximate to the guide.

Advantageously, the torsionally elastic shaft is formed by a cable orstrip secured by a spring. In this manner, overloading of the cable canpositively be prevented.

BRIEF DESCRIPTION OF THE DRAWING

The invention will now be explained in further detail with reference tothe drawing, in which:

FIGS. 1 and 2 show schematically two different embodiments of devicesaccording to the invention,

FIG. 3 shows a schematic, sectional view of a device according to theinvention, and

FIGS. 4 and 5 show further embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the embodiments according to FIGS. 1 and 2, there is provided a fixedguide 1 provided with bores arranged concentrically with respect to acenter axis for receiving individual wires 2.

Subsequent to the fixed guide 1 there are arranged essentially equallyspaced storing disks 4 along the pulling direction of the individualwires 2 which is indicated by arrows 3, wherein the storing disks 4 arealso provided with bores arranged concentrically with respect to arotation axis of the string disks 4 for receiving individual wires 2. Inthis case, the storing disks 4 and,a laying disk 6 are capable of beingdriven in changing directions.

A cable guide 5 is provided following the laying disk 6 through whichthe cable is withdrawn.

The storing disks 4 and the laying disk 6 are each driven via atransmission member 9, such as a belt, by the drive disks 7 which arecoupled to a motor 8.

In both embodiments, a torsion spring 15 is provided as a couplingelement which in the embodiment of FIG. 1 is secured to a part of theframe in the area of a fixed guide 1'.

In the embodiment of FIG. 2, the torsion spring 15 is provided only fora portion of the storing disks 4, i.e. coupled to the two laying disksclosest to the motor 8.

In both embodiments, the drive disks 7 are coupled to the storing disks4 and the laying disk 6, respectively, via the belt 9. In this case, forall of the drive disks 7 coupled to the torsion spring 15 the same speedincreasing ratio may be provided with respect to the associated storingdisks 4 and laying disk 6, respectively.

In the embodiment of FIG. 2, the two drive disks 7 closest to the fixedguide 1 are coupled together via a rigid shaft 10 which is in turncoupled at 16 to the torsion spring 15. In contrast to the speedincreasing ratio of the two drive disks 7 closest to the motor 8,however, the speed increasing ratios for these drive disks with respectto their associated storing disks 4 may be different.

At the rotatably supported end of the rigid shaft 10 facing away fromthe coupling 16, a limit stop is provided for limiting the twistingangle of the storing disk 4 at that respective position, the positionsof the limit stop being arranged in such a way that the respectivestoring disk 4 is capable of rotating in both SZ-directions by thecorresponding rotation angle.

The difference of the twisting angles between the storing disk 4 whichis closest to the fixed guide 1 and is still or is already driven by thespring, and the laying disk 6 has to be equal or larger than thetwisting angle required by the laying disk for acceleration. In thisway, the motor can be rapidly brought to its nominal speed and thereversing region from left to right or vice versa on the stranded itemcan be kept short.

FIG. 3 shows that the motor 8 and its shaft 11, respectively, arecoupled in a torsion-free manner to the drive disk 7 which, in turn, iscoupled in a torsion-free manner to the torsion spring 15. The drivedisk 7 associated with the storing disk 4 closest to the motor 8 is alsocoupled in a torsion-free manner to the torsion spring 15, with thetorsion spring 15 fixedly secured in a support 1 which is in turnsupported by a frame portion 13 of the device.

In the embodiment of FIG. 4, the torsion spring 15 is replaced by atorsion bar 15 which provides an identical effect and function as if atorsion spring 15 was used.

FIG. 5 shows an embodiment where the torsionally elastic shaft is formedby at least one taught, extendible filament-shaped or strip-shapedelement 18 which is guided through eccentrically arranged bores 19 ofthe drive disks 7 and secured to the drive disk 7 closest to the motor8, wherein the eccentricity of the bores in the drive disks 6 which arepenetrated by the filament-shaped element, may increase in the directiontowards the motor 8. The cable or strip 18 is preferably secured by aspring which is not shown. Alternatively or in addition, the cable mayalso comprise an elastically extendible material, such as rubber,plastic or the like, and may not be prestressed.

What is claimed is:
 1. A device for making a wire strand with changingtwist direction (SZ-stranding) from individual wires, comprising:a fixedguide provided with bores for passage of individual wires; a pluralityof storing disks trailing the fixed guide and arranged in spaced-apartdisposition, said storing disks having bores for passage of theindividual wires to be stranded; a laying disk trailing the plurality ofstoring disks; and drive means for operating the storage disks and thelaying disk in changing directions, said drive means including aplurality of drive disks and a like plurality of transmission members,said drive disks and said transmission members being so positioned thateach of the storage disks and the laying disk are operatively connectedto a different one of the drive disks via a different one of theintermediate transmission members, said drive means further including amotor operatively connected to at least some of the drive disks, and atorsionally elastic shaft having a random cross-section and extendingbetween the motor and the drive disks.
 2. The device of claim 1, andfurther comprising a rigid shaft for coupling at least two neighboringdrive disks, with said neighboring drive disks and the associatedstorage disks having different transmission ratios.
 3. The device ofclaim 1 wherein the torsionally elastic shaft is maintained undertension.
 4. The device of claim 1 wherein the torsionally elastic shaftis formed as an element selected from the group consisting of torsionspring and torsion bar, and connected to the drive disks in atorsion-free manner.
 5. The device of claim 4 wherein the torsionallyelastic shaft has a spring constant increasing in the direction towardsthe motor.
 6. The device of claim 1 wherein the torsionally elasticshaft is formed by at least one tensed, extendible filament-shaped orstrip-shaped element which is guided through eccentrically arrangedbores of the drive disks and secured to the drive disk closest to themotor.
 7. The device of claim 6 wherein the eccentricity of the bores inthe drive disks increases in the direction towards the motor.
 8. Thedevice of claim 1 wherein the torsionally elastic shaft is formed by acable or strip secured by a spring.